As shown in FIG. 1, a conventional method for integrating multi-layer sheet fabric pieces for use in a chemical protective suit carried out for producing a chemical protective suit comprises the steps of (a) stacking one piece 12 of a pair of multi-layer sheet fabric pieces 12, 13, each of which comprises a front surface layer of synthetic rubber film, a rear surface layer of synthetic rubber film, and at least one middle layer of chemical permeability resistant resin film, on the other piece 13 of the pair of multi-layer sheet fabrics 12, 13, with a part 12a of a peripheral edge of the multi-layer sheet fabric piece 12 opposed to a part 13a of a peripheral edge of the multi-layer sheet fabric piece 13, (b) seaming the stacked multi-layer sheet fabric pieces at a portion close to the peripheral edges 12a, 13a opposed to each other along the peripheral edges 12a, 13a so as to form a seam line 14, (c) folding the multi-layer sheet fabric piece 12 toward the seam line 14 at a portion away from the seam line 14 beyond a band portion of predetermined breadth so as to form a folding line 12b, wherein the peripheral edge 12a and the band portion are disposed to face the opposite sides of the seam line 14, (d) seaming the triply stacked multi-layer sheet fabric pieces at a portion close to the folding line 12b so as to form a seam line 15, (e) sticking a synthetic rubber tape 16 on the multi-layer sheet fabric pieces 12, 13 so as to cover a portion of the multi-layer sheet fabric piece 12 of predetermined breadth at one side of the folding line 12b, a portion of the multi-layer sheet fabric piece 13 of predetermined breadth at the other side of the folding line 12b, and the folding line 12b by the synthetic rubber tape 16, (f) welding the stacked potions of the synthetic rubber tape 16 and the multi-layer sheet fabric pieces 12, 13 using an external heat source so as to integrate them with each other, and (g) sticking a rubber coated sheet fabric piece 17 on the multi-layer sheet fabric pieces 12, 13 so as to cover a portion of the multi-layer sheet fabric piece 12 of predetermined breadth at one side of the peripheral edges 12a, 13a, a portion of the multi-layer sheet fabric piece 13 of predetermined breadth at the other side of the peripheral edges 12a, 13a, and the peripheral edges 12a, 13a. When the chemical protective suit is completed, the synthetic rubber tape 16 is exposed to the external air and the rubber coated sheet fabric piece 17 is exposed to the internal air of the suit.
In the aforementioned method, air tightness and chemical permeability resistance are achieved by sticking the synthetic rubber tape 16 on the outside surface of the stacked portion of the multi-layer sheet fabric pieces 12, 13 and the folding line 12b, welding the synthetic rubber tape 16, and sticking the rubber coated sheet fabric piece 17 on the inside surface of the stacked portion of the multi-layer sheet fabric pieces 12, 13 and the peripheral edges 12a, 13a so as to shut the spaces among the stacked sheet fabric pieces 12, 13 off from the internal air and the external air.